A teenager, male or female, usually in the range of 13-16 years old, who likes to go wild and have a good time.
Their activities are not necessarily bad, but definately against the rules. Often sneak out of the house in the dead of night.

I was less a wild child and more of a depraved pyromaniac, burning down telephone poles on the weekends.

A human child who has lived in social isolation from a very young age and therefore has no knowledge of the world, language, or social behavior. Some wild children have been neglected by insane parents; others are children who have grown up and survived in the wild. They are extremely rare, but when discovered, cause quite a sensation, esp with psychologists.

aka feral child, savage

'Viktor' was found in the woods in France around 1800. He apparently grew up alone as a savage in the wild.

'Genie' was found in 1970 in LA neglected for almost her entire 13 yr life stuck on a potty chair in a room.

In both cases, there was only partial success in trying to make these wild children 'normal.'